Streptavidin is important in many biomedical technologies, including bioseparations, diagnostics, and drug delivery. It also possesses unique self-assembly properties. This project is aimed at using the self-organizing capabilities of streptavidin to produce protein monolayers with well-defined structural hierarchy. These ordered protein monolayers will provide model systems for fundamental studies on ESCA and SIMS applications. In addition, the simultaneous capabilities of streptavidin to self-organize and to bind a second biomolecular layer holds great promise as a tool for controlled biomedical studies and for biomedical technology development. Through an exploration of fundamental relationships between surface chemistry and biocompatibility, for e example, this promise will also be developed in the project.